There is a metallic sealing member for withstanding use in a harsh condition, preventing leakage of fluid and having airtightness and liquid tightness etc. in structure.
In the case where this metallic sealing member is brought into contact with an object to be sealed by a flat surface, if a front surface is rough, a minute clearance is formed between the sealing member and the object and leakage of fluid occurs. Therefore, as described in, for example, Patent Literature 1, machining such as arc-shaping or sharpening of a contacting portion between the metallic sealing member and the object to be sealed is performed.